The headlamp, referred to by some as the “eyes” of a car, is very important to traffic safety. The early car headlight only includes low-beam and high-beam modules, so that light distribution patterns provided thereof are stationary and cannot be adjusted according to the car's driving conditions and the changes of the external environment. Therefore, the use of the aforesaid car headlight has many disadvantages. For example, when a vehicle, in which the headlight has a near illumination distance, is driving on a highway, the driver cannot respond immediately to a sudden accident. In addition, when a vehicle, in which the headlight has a narrow illumination distance, is driving on a town road, rainy road, or curve, there may exist light-dark areas at front left and front right sides of the vehicle and thus the driver may ignore road conditions of road sides and result in a traffic accident.
With the advancement of technology, more and more headlights using the adaptive front-lighting system (AFS) are provided. Such headlights can be controlled by the AFS to rotate in the left-right or up-down direction according to a rotation angle of the steering wheel, a driving speed and a car turning radius. Accordingly, the headlights would provide a light distribution patterns complying with current road environments and an illumination direction same as the driving direction. Therefore, the driver would have the best view field and safe illuminations under various road environments can be ensured. However, such headlights have a complicated structure and require a plurality of driving devices to respectively control the movements in the left-right and up-down directions of the light distribution patterns.
In order to convert the light distribution pattern, a common way is using different modules that cooperate with each other. For example, some of the modules for producing a high-beam light-condensing pattern, a low-beam light-condensing pattern, a low-beam light-diffusing pattern, and other light distribution patterns can be turned on or off. Another common way is using a converting mechanism such as a drum, which is provided with different light distribution patterns each having a cut-off line, to being rotated a desired light distribution pattern to the focal point of the lens for projection. However, these ways cannot meet the requirements of miniaturization, light weight, and low cost, and the optical designs thereof are complicated and difficult for population. In addition, these ways may occupy a large amount of space and thus there is insufficient space in the front of the car body for the installation of the cornering light.